1. Field of the Invention
The present invention relates to a heat exchanger which can effectively be applied to an intercooler for cooling air (intake air) which is induced into an internal combustion engine to support combustion.
2. Description of the Related Art
FIG. 7A is a front view of an intercooler which has been being made, on an experimental basis, for a study by the inventor, et al, and FIG. 7B is an enlarged view of a portion of the intercooler indicated by an arrow B in FIG. 7A. In this experimentally studied intercooler, reinforcement plates (inserts) 130 and core plates 121 are brazed together with longitudinal end portions of the inserts 130 being inserted into holes formed in longitudinal end portions of the core plates 121.
Due to this, there remains a large amount of flux at the end portions of the core plates 121 where the inserts 130 are inserted, and this residual flux deteriorates the weldability between a tank main body 122 and the core plate 121.
On the other hand, as shown in FIG. 8A, a part of the core plate 121 is extended onto the insert 130 so that a portion so extended (an extension 123) is then inserted in the insert 130 for brazing. This can prevent the accumulation of such a large quantity of flux at the portion of the core plate 121 where the tank main body 122 is welded. As shown in FIG. 8B, however, as a contact area between the extension 123 and the insert 130 is small, it is difficult to secure a required brazing reliability.
The present invention was made in view of these problems, and an object thereof is to improve the weldability between the core plate and the tank main body and to ensure that the core plate (the extension) and the insert (the reinforcement plate) are brazed together properly.
With a view to attaining the object, according to an aspect of the invention, there is provided a heat exchanger comprising a plurality of tubes (111) through which fluid flows, fins (112) joined to external surfaces of the plurality of tubes (111) for promoting heat exchange between fluid flowing between the plurality of tubes (111) and fluid flowing through the interior of the plurality of tubes (111), reinforcement plates (130) disposed at end portions of a core portion (110) constituted by the plurality of tubes (111) and the fins (112) in such a manner as to extend substantially in parallel to the plurality of tubes (111) so as to reinforce the core portion (110), and header tanks (120) disposed at longitudinal end portions of the plurality of tubes (111) in such a manner as to extend in a direction normal to the longitudinal direction of the plurality of tubes (111) and adapted to communicate with the plurality of tubes (111), wherein the header tank (120) is constituted by a core plate (121) to which the plurality of tubes (111) are joined and a tank main body (122) welded to the core plate (121) so as to constitute a space in the interior of the header tank (120), wherein extensions (123) are provided at longitudinal end portions of the core plate (121) which each have a width (Wc) which is substantially the same as the width (Wi) of the reinforcement plate (130) and extend onto longitudinal end portions of the reinforcement plates (130), respectively, so as to be brazed thereto, and wherein holding portions (131) are further provided at the longitudinal end portions of the reinforcement plates (130) so as to hold therein the extensions (123), respectively.
Thus, according to this aspect of the invention, as the extension (123) of the core plate (120) is brazed to the reinforcement plate (130) with the extension (123) being held in the holding portion (131) formed on the reinforcement plate (130), different from the case with the experimentally studied intercooler described above, flux hardly remains at the longitudinal end portions of the core plates (121). Consequently, the tank main body (122) can easily be welded to the core plate (121).
In addition, as the extension (123) has the width (Wc) which is substantially the same as the width (Wi) of the reinforcement plate (the insert) (130), the contact area between the extension (123) and the reinforcement plate (130) can be made larger than the contact area of the experimentally studied intercooler, whereby it is possible to ensure that the extension (123) and the reinforcement plate (130) are brazed together properly.
As has been described heretofore, according to this aspect of the invention, as the welding of the core plate (121) to the tank main body (122) can be improved and the brazing of the core plate (121) (the extension (123)) to the reinforcement plate (130) can be ensured, the reliability (durability) of the heat exchanger can be increased.
In addition, the holding portion (131) is desirably formed by deviating a portion of the reinforcement plate (130) which is defined by adjacent cut portions (132) in a thickness direction of the reinforcement plate (130).
According to another aspect of the invention, the extension (123) is formed integrally with the core plate (121) in such a manner that the surface of the extension (123) continuously smoothly connects to the surface of the core plate (121).
According to this aspect of the invention, as the tank main body (122) can deviate in the longitudinal direction, a dispersion of production quality (in dimensions) of the core plates (121) and the main tanks (122) can be absorbed. Hence, the generation of a gap attributed to the dispersion of production quality (in dimensions) can be suppressed which will be described herein, later, with reference to FIG. 5B.
The present invention may be more fully understood from the description of a preferred embodiment of the invention, as set forth below, together with accompanying drawings.